Dear Alex,

           Thank you. We can get a maximum of about 7% extra in the force with 2 coils. 
 I wish to know what happens with interposition of a mesh or strings, which is magnetisable when placed at the maximal field density outside the coil. The nickel strings with a a perpendicular strings interposed as an electric current. The strings can be 50 micro m thick, 75 micro m width and 100 micro m pitch or you can assume a uniform about 60 micro m. I can understand that you can model as strings only. However, it is fine. We will see what happens. This is very interesting. We will use the same 5T magnetic strength.

with regards,
Mark





Dear Mark,

	So far I have simulated a single ferromagnetic (Ni) ring in the static field of the coil. The ring is placed 5 cm away from the coil and has inner diameter of 100 micrometers.
	The ring pulls magnetic field inside ferromagnetic body producing high gradient magnetic field in nearby space. The effect is prominent in short range only (0.3 mm), further away the field distribution becomes regular, as if there is no ring at all.

	I have no experience with strings so I stop for now (1 hrs spent) and are waiting for your suggestions. What should I simulate next? Should I place several rings concentrically to find if the magnetic field distortion will propagate further?


Best regards,
	Alex